Early Permian Glossopteris flora from the Sharda Open Cast Mine, Sohagpur Coalfield, Shahdol District, Madhya Pradesh

(1)

Early Permian Glossopteris flora from the Sharda Open Cast Mine, Sohagpur Coalfield, Shahdol District,

Madhya Pradesh

DEEPA AGNIHOTRI

^1*

, RAJNI TEWARI

¹

, S.S.K. PILLAI

¹

, ANDRÉ JASPER

²

AND

DIETER UHL

³

1Birbal Sahni Institute of Palaeobotany, 53 University Road, Lucknow 226 007, India.

2Programa de Pós–Graduação em Ambiente e Desenvolvimento, PPGAD. Centro Universitário Univates, Lajeado, Brazil.

3Senckenberg Forschungsinstitut und Naturmuseum, Frankfurt am Main, Germany.

*Corresponding author: [email protected]

(Received 23 February, 2016; revised version accepted 14 March, 2016)

ABSTRACT

Agnihotri D, Tewari R, Pillai SSK, Jasper A & Uhl D 2016. Early Permian Glossopteris flora from the Sharda Open Cast Mine, Sohagpur Coalfield, Shahdol District, Madhya Pradesh. The Palaeobotanist 65(1): 97–107.

Well preserved plant fossil assemblage recorded for the first time from the Barakar Formation of Sharda Open Cast Mine, Sohagpur Coalfield, Shahdol District, Madhya Pradesh is documented in this study. The assemblage comprises the orders Equisetales, Glossopteridales and Cordaitales. Equisetales is represented by unidentifiable leafless equisetalean axes bearing nodes and internodes, Glossopteridales comprises one species of Gangamopteris (Gangamopteris intermedia) and seven species of Glossopteris (Glossopteris communis, G. gigas, G. giridihensis, G. indica, G. longicaulis, G. spatulata and Glossopteris sp.), and Cordaitales is known by one species of Noeggerathiopsis (Noeggerathiopsis hislopii). The floral assemblage is broadly comparable with those described previously from the Barakar Formation of Damodar, Mahanadi, Wardha, Godavari, Rajmahal and Satpura Gondwana basins of India. Since the known records of plant mega fossils from the Barakar Formation of Sohagpur Coalfield are meagre, recovery of quantitatively and qualitatively rich plant fossils from the Sharda Open Cast Mine substantiates the geological and geographical distribution of the Glossopteris flora in India in general and that of the Sohagpur Coalfield in particular, and reflects its significance in the formation of coal in the area.

Key–words—Glossopteris flora, Early Permian, Barakar Formation, Sharda Open Cast Mine, Sohagpur Coalfield.

'kkjnk foo`r [kku] lksgkxiqj dks;yk{ks=k] ftyk 'kgMksy] e/; izns'k ls izkjafHkd ifeZ;u XykWlkWIVsfjl ouLifr lewg

nhik vfXugks=kh] jtuh frokjh] ,l-,l-ds- fiYyS] vkanzs tkLij ,oa MhVj my lkjka'k

'kkjnk foo`r [kku] lksgkxiqj dks;yk{ks=k] ftyk 'kgMksy] e/; izns'k ds cjkdkj 'kSylewg ls igyh ckj izkIr lqifjjf{kr ikni thok'e leqPp; bl v/;;u esa izysf[kr fd, x, gSaA leqPp; esa bDohflVsYt+] XykWlkWIVsjhMsYt+ ,oa dkWMkZbZVsYt+ dksfV lfUufgr gSA bDohflVsYt+ xkWaB ,oa var%xkWaB /kkjh vufHkKs; i.kZjfgr bDohflVsfy;u ruksa ls :ikf;r gS] XykWlkWIVsjhMsYt+ xSaxsekWIVsfjl dh ,d tkfr ¼xSaxsekWIVsfjl baVjehfM;k½ vkSj XykWlkWIVsfjl dh lkr tkfr;ksa ¼XykWlkWIVsfjl dE;qful] th- tkbxl] th- fxfjfMgsfUll] th- bafMdk] th- ykWaxhdkWfyl] th- LispqysVk vkSj XykWlkWIVsfjl tkfr½ ls lfUufgr gS rFkk dkWMkZbZVsYt+uSxsjsfFk;ksfIll dh ,d tkfr ¼ uSxsjsfFk;ksfIll fgLyksikbZ½ ls Kkr gSA ikni leqPp; eksVs rkSj ij Hkkjr dh nkeksnj] egkunh] o/kkZ] xksnkojh] jktegy ,oa lriqM+k xksaMokuk nzksf.k;ksa ds cjkdkj 'kSylewg ds iwoZ of.kZr XykWlkWIVsfjl ouLifr lewg ds rqY; gSA pwafd lksgkxiqj dks;yk{ks=k ds cjkdkj 'kSylewg ls izkIr ikni LFkwy thok'eksa ds Kkr vfHkys[k de gSa] 'kkjnk foo`r [kku ls ek=kkRedrk o xq.kkRedrk izpqj ikni thok'eksa dh izkfIr] lkekU;r% Hkkjr esa XykWlkWIVsfjl ouLifr lewg ds Hkw&oSKkfud o HkkSxksfyd forj.k rFkk fo'ks"kr;k lksgkxiqj dks;yk{ks=k dh vkSj {ks=k esa dks;yk mRifRr esa] bldh egRrk dks izfr LFkkfir djrk gSA

lwpd 'kCnµXykWlkWIVsfjl ouLifr lewg] izkjafHkd ifeZ;u] cjkdkj 'kSylewg] 'kkjnk foo`r [kku] lksgkxiqj dks;yk{ks=kA

(2)

98 THE PALAEOBOTANIST

Fig. 1—Geological map of Sohagpur Coalfield showing the fossil locality.

INTRODUCTION

T

^HESohagpur Coalfield is the major coal producing area of South Rewa Gondwana Basin and occupies an east–trending rectangular area in the west–central part of the basin. The coal bearing area lies between latitudes 23°05'−23°30ꞌ and longitudes 81°13ꞌ−82°12ꞌ (Fig. 1) and is situated in the Shahdol District, Madhya Pradesh (Raja Rao, 1983). The Barakar Formation is the only coal bearing formation in the coalfield. The coal is being exploited by South Eastern Coalfields Limited (SECL− a subsidiary of Coal India Limited). On the basis of occurrence of coal, the coalfield is divided mainly into three sub basins− Jhagrakhand–Bijuri, Kotma and Burhar–Amlai. The present study area–the Sharda Open Cast Mine (OCM)–is a part of the Burhar–Amlai sub basin.

Previous records of the plant megafossils from the Sohagpur Coalfield are sporadic. Hughes (1881, 1884) and Feistmantel (1882) reported the plant fossils from the Talchir and Barakar formations of Sohagpur Coalfield. Later on, Chandra and Srivastava (1982) recorded some Glossopteris floral elements from the Talchir Formation and the coal bearing horizon of the Anupur area of this coalfield.

The present paper entails a systematic and detailed morphotaxonomic study of macrofloral assemblage of the Barakar Formation recorded from the grey carbonaceous shale associated with Burhar seam IV and Burhar VI bottom seam of the Sharda Open Cast Mine (Fig. 2). The assemblage comprises pteridophytes and gymnosperms. The pteridophytes are represented by a single order Equisetales, and the gymnosperms are represented by the Glossopteridales and Cordaitales.

GEOLOGICAL SETTING

The Sohagpur Coalfield comprises over 1,000 m thick sedimentary strata. The Gondwana sedimentary rocks in the area strike WNW–ESE to E–W and dip up to 5° towards north (Pareek, 1987). The Talchir sediments (early Permian) consist of shale, siltstone and boulder beds and unconformably overlie the basement rocks. The overlying 450 m thick Barakar Formation (early Permian) is composed of sandstones with bands of shale, carbonaceous shale and coal seams. This coal bearing formation is subdivided into three members lower, middle and upper. The lower member conformably overlies the Talchir Formation and includes a greyish–white

(3)

Fig. 2—Litholog of Sharda OCM showing the plant fossil bearing horizons..

feldspathic garnet sandstone, siltstone and shale, and is devoid of coal seams. The middle member has the maximum thickness and contains cross–bedded feldspathic sandstones with garnet, and thick workable coal seams in the lower portion. The upper member includes ferruginous sandstones, shales, and siltstones. The Pali Formation (late Permian/

early Triassic), which overlies the Barakar Formation, is approximately 350 m thick. The Parsora Formation (early Jurassic) is found in the northern part of the basin and includes coarse–grained to pebbly ferruginous sandstones and shales.

The overlying Lameta beds (late Cretaceous) contain greenish and reddish, poorly consolidated sandstones and shales with nodular limestone at the top. These beds are separated from the Parsora Formation by a marked unconformity. The coalfield is intruded by dykes and sills (Deccan Trap–late Cretaceous–Eocene). Dolerites are also emplaced along the faults (Dhanam et al., 2013).

The Sharda Open Cast Mine is located in the eastern part of the Burhar–Amlai sub basin of the Sohagpur Coalfield and was started in the year 1986. The area has gently undulating terrain with elevations ranging from 450 to 480 m above the Mean Sea Level. The mine is situated in 6 km east of the Burhar Town in the Sohagpur area and lies approximately between latitudes 23°12ꞌ10"−23°13ꞌ45" and longitudes 81°35ꞌ12"−81°38ꞌ08" (Fig. 1). In the Sharda Open Cast Mine, 0.85 million tons of coal is being exploited per annum by high wall mining technique.

MATERIAL AND METHOD

The present study is based on megafossil samples collected from the Barakar Formation of the Sharda Open Cast Mine, Sohagpur Coalfield, Shahdol District, Madhya Pradesh.

Plant fossils have been collected from the carbonaceous grey shales above the seam IV and the carbonaceous shales below the Burhar VI bottom seam of the Sharda Open Cast Mine (Fig. 2). The plant fossils are preserved as impressions on shales with fine details of the venation and gross leaf morphology. Around 45 specimens have been studied. The leaves were studied and identified using a hand lens and a low–

power binocular microscope (Olympus SZH). Identifications are made according to the leaf shape, nature of apex, base, midrib and venation pattern. We have adopted the terminology given by Lawrence (1955) for the precise determination of the leaf shape, apex and base. For the venation pattern, terminology provided by Melville (1969) and Chandra and Surange (1979) is followed. All the type and figured specimens are deposited in the Repository of the Birbal Sahni Institute of Palaeobotany (BSIP), Lucknow, India vide BSIP Museum Statement No. 1425.

SYSTEMATICS Order—EQUISETALES

Equisetalean axes (Pl. 1.1; 1.2)

Description—Unbranched axes with well–preserved nodes and internodes measuring 90–290 mm long and 24–29 mm wide are available in the collection. The distance between nodes is 48 mm, nodes are 1.5 mm wide, vascular bundles alternating at nodes, vascular bundles are 2 mm apart.

Remarks—Sphenophyte axes with vascular bundles that alternate at the nodes occur in most families of Equisetales (e.g. Calamitaceae, Equisetaceae). Such axes without leaves or fertile structures can thus only be determined up to the order Equisetales.

No. of specimens—Two (40895A, 40895B).

(4)

Order—GLOSSOPTERIDALES Genus—GANGAMOPTERIS McCoy, 1875 Type species—Gangamopteris angustifolia McCoy, 1875

Gangamopteris intermedia Maithy, 1965 (Pl. 1.3)

Description—A single leaf is present in the collection.

Leaf almost complete, small, 35 mm long and 16 mm broad, shape ovate, apex broad, base narrow. Median region is occupied by 5 parallel veins, cross connections are present.

Secondary veins arise at about 18º and meet the margin at about 50º. During the course, veins dichotomize and anastomose to form oblong, broader and longer meshes near median region and narrower and shorter ones near the margin.

Meshes are 4−5 mm long and 0.4−0.6 mm broad near the median region, 2−3.5 mm long and 0.2−0.3 mm broad near the margin. Vein density is 12−16 per cm near the median region and 18−23 per cm near the margin.

Remarks—The leaf is identical in shape, size, nature of apex, base and venation pattern to Gangamopteris intermedia

Maithy (1965, Pl. 3, fig. 21, Pl. 4, figs 22, 24), Chandra and Srivastava (1982, Pl. 1, fig. 4) and Maithy et al. (2006, Pl.

1, fig. 6).

No. of specimens—One (40896).

Genus—GLOSSOPTERIS Brongniart, 1828 Type species—Glossopteris browniana Brongniart, 1828

Glossopteris communis Feistmantel, 1876

(Pl. 1.4–1.8)

Description—Leaves incomplete, different parts of apical, middle and basal portions of leaf lamina are preserved.

Size of the leaves ranges from 54 to 150 mm in length and from 24 to 56 mm in width. Leaves are elliptic–lanceolate, apex obtuse to slightly acute, base narrow, margin entire.

Midrib flat, striate, 2–4 mm wide, secondary veins arise from midrib at about 19°–25° and meet the margin at about 45°–60°.

After dichotomizing and anastomosing, the secondary veins form arcuate, narrow, elongate meshes. Meshes are 4–6 mm long and 0.2–0.5 mm wide throughout the lamina. Venation dense, density of veins is 15–21 per cm.

PLATE 1

(Scale bar= 1 cm) 1. Equisetalean axis, BSIP Museum Specimen No. 40895A (nodes are

indicated by arrows).

2. Equisetalean axis, BSIP Museum Specimen No. 40895B.

3. Gangamopteris intermedia Maithy, 1965, BSIP Museum Specimen No. 40896.

4. Glossopteris communis Feistmantel, 1876, BSIP Museum Specimen No. 40897.

5. Glossopteris communis Feistmantel, 1876, BSIP Museum Specimen

No. 40898A.

6. Glossopteris communis Feistmantel, 1876, BSIP Museum Specimen No. 40899A.

7. Glossopteris communis Feistmantel, 1876, BSIP Museum Specimen No. 40903A.

8. Glossopteris communis Feistmantel, 1876, BSIP Museum Specimen No. 40901.

Name of taxa Gondwana basins of India

Damodar Mahanadi Wardha–

Godavari Satpura South

Rewa Rajmahal

Equisetalean axes * * * * * *

Gangamopteris intermedia * *

Glossopteris communis * * * * * *

Glossopteris gigas * * * *

Glossopteris giridihensis * * *

Glossopteris indica * * * * * *

Glossopteris longicaulis * * * *

Glossopteris spatulata * * * * *

Glossopteris sp.

Noeggerathiopsis hislopii * * * * * *

Table 1—Distribution of plant fossil taxa of the Sharda OCM in the Barakar Formation of other Gondwana basins of India.

(5)

PLATE 1

(6)

Remarks—This is the most common species of the genus Glossopteris and is recorded from all the lower Gondwana basins of India. The leaves are identical in venation pattern to G. communis recorded by Feistmantel (1879, Pl. 17, figs 1, 2), Feistmantel (1882, Pl. 21, figs 13, 14), Feistmantel (1890, Pl.

17, figs 2, 6), Chandra and Surange (1979, Pl. 1, figs 2, 3), Pant and Gupta (1968, Pl. 26, figs 44–49, text–fig. 14), Chandra and Srivastava (1982, Pl. 4, fig. 29), Maheshwari and Tewari (1992, Pl. 1, fig. 2), Singh et al. (2006a, Pl. 4, fig. 3), Tewari (2008, Pl. 2, fig. 7) and Tewari et al. (2012 , figs 5K, L).

No. of specimens—Twelve (40897, 40898A, 40899A, 40900A, 40900B, 40901, 40902, 40903A, 40903B, 40904, 40905, 40906).

Glossopteris gigas Pant & Singh, 1971

(Pl. 2.1–2.3)

Description—Five incomplete leaves are present in the collection. Leaves measure 129–220 mm in length and 26–126 mm in width. Shape apparently ovate, apex broad rounded, base broken, margin entire. Midrib is distinct, flat, striate, persistent, 6 mm wide at base, thinning towards apex, 2 mm wide in apical region. Secondary veins arise at about 40°–45°

from the midrib and arch slightly to meet the margin at about 75°–80°. After dichotomizing and anastomosing, they form narrow, elongate meshes throughout the lamina. Meshes are 6–9 mm long and 0.3–0.7 mm broad. The density of veins is 11–20 veins per cm.

Remarks—Leaves resemble the specimens of Glossopteris gigas described by Pant and Singh (1971, Pl.

3, figs 10, 14) and Chandra and Surange (1979, Pl. 12, fig.

1, Pl. 25, fig. 1), respectively, in shape, large size, nature of the midrib and venation pattern. The present leaves are also identical to G. gigas figured by Chandra and Singh (1992, Pl.

3, fig. 3, Pl. 6, fig. 1), Tewari (2007, Pl. 2, fig. 3, Pl. 3, fig. 2) and Singh et al. (2011, Pl. 6, figs 2, 4).

No. of specimens—Five (40907, 40908, 40909, 40910, 40911).

Glossopteris giridihensis Pant & Singh, 1971 (Pl. 2.4)

Description—A single specimen is present in the collection. Leaf incomplete, only middle part is preserved.

Size of the leaf fragment is 49 mm in length and 10 mm in width. Shape narrow, oblong, apex and base are absent.

Midrib is striate, 3 mm broad in lower region and 2 mm in upper region. Secondary veins arise from midrib at about 19°, slightly arch and meet the margin at about 74°. During their course, the veins dichotomize and anastomose to form narrow, elongate meshes. Meshes are 3–5 mm long and 0.2–0.5 mm broad. Density of veins is 11–17 veins per cm.

Remarks—The leaf is consistent with Glossopteris giridihensis described by Pant and Singh (1971,Pl. 20, fig.

29) in small size, shape and venation pattern. The present leaf also resembles Glossopteris giridihensis figured by Chandra and Surange (1979, Pl. 47, fig. 4) and Singh and Saxena (2015, Pl. 6, fig. 2) in having similar venation pattern. However, Singh and Saxena (2015) reported the species from the late Permian sediments.

No. of specimens—One (40912A).

Glossopteris indica Schimper, 1869

(Pl. 2.5–2.7)

Description—Eight incomplete leaves are present in the collection. Shape is oblanceolate, elliptic, apex absent, base long, narrow, attenuate, margin entire. Size of leaves ranges from 70–212 mm in length and 29–87 mm in width, midrib distinct, striate, elevated, persistent, 3–6 mm wide at basal region, thinning towards the apex. Secondary veins arise at about 23°–35° from the midrib, slightly arch and meet the margin at about 51°–68°. Veins dichotomize and anastomose to form meshes. Meshes are short, broad, arcuate, 2–4 mm long and 0.6–0.9 mm broad near the midrib, and long, narrow, 6–8 mm long and 0.2–0.4 mm wide elsewhere. The density of veins is 9–16 per cm near the midrib and 22–30 near the margin.

Remarks—Leaves are identical to G. indica Schimper described by Chandra and Surange (1979, Pl. 5, fig. 1, Pl. 10, fig. 4, Pl. 15, fig. 11, Pl. 28, fig. 1, Pl. 29, fig. 1), Tewari and Srivastava (2000a, Pl. 1, fig. 4), Tewari (2007, Pl. 1, fig. 4, Pl.

3, fig.1, Pl. 4, fig. 2, Pl. 6, figs 5,7), Tewari (2008, Pl. 4, fig.

4), Singh et al. (2011, Pl. 7, figs 2, 4), and Tewari et al. (2012, figs 6E–H) in shape, nature of the midrib and venation pattern.

PLATE 2

(Scale bar= 1 cm)

1. Glossopteris gigas Pant & Singh, 1971, BSIP Museum Specimen No.

40907.

40910.

40911.

4. Glossopteris giridhiensis Pant & Singh, 1971, BSIP Museum Specimen

No. 40912A.

5. Glossopteris indica Schimper, 1869, BSIP Museum Specimen No.

40918.

40912B.

40915.

(7)

PLATE 2

(8)

No. of specimens—Eight (40912B, 40913, 40914, 40915, 40916, 40917, 40918, 40919).

Glossopteris longicaulis Feistmantel, 1879 (Pl. 3.1)

Description—Two incomplete specimens are present in the collection. Size of leaves ranges from 162 to 220 mm in length and 43 mm in width. Leaves are distinctly petiolate, oblong–lanceolate in shape, apex not preserved, base narrow–

tapering, margin entire. Midrib is distinct, striate, 4 mm broad, petiole 20 mm long, striate and 6 mm wide. Secondary veins arise at about 18°–20° from the midrib and arch to meet the margin at 45° after dichotomizing and anastomosing. Meshes are arcuate, 5–8 mm long and 0.5–0.9 mm broad near the midrib and 2–4 mm long and 0.2–0.3 mm broad near the margin. The density of veins is 11–14 per cm near the midrib and 19–24 per cm near the margin.

Remarks—The leaves are consistent with Glossopteris longicaulis Feistmantel (1879) as illustrated by Chandra and Surange (1979, Pl. 1, fig. 4, Pl. 15, fig. 13) in having similar nature of midrib, petiole and venation pattern. They also match G. longicaulis described by Singh et al. (1982, Pl. 5, figs 31, 32, text–fig. 7f), Tewari (2008, Pl. 4, fig. 8) and Tewari et al.

(2012, figs 6K, L).

No. of specimens—Two (40898B, 40932).

Glossopteris spatulata Pant & Singh, 1971

(Pl. 3.2–3.4)

Description—Four leaves are present in the collection of which one is preserved as part and counterpart. Leaves are 130–165 mm long and 55–88 mm broad, shape spatulate, apex rounded, base narrow, midrib persistent, striate, 2 mm broad in the lower part and 1 mm broad in the upper part, margin entire. Secondary veins arise at about 40°–45° and meet the margin at about 60°–65° after dichotomization and anastomosis. Meshes are long, narrow, arcuate, 6–8 mm long and 0.5–0.8 mm broad near the midrib and narrow, shorter, trapezoid, 1.5–4 mm long and 0.2–0.5 mm broad near the

margin. Venation dense, density of veins is 16–25 per cm near the midrib and 24–31 per cm near the margin.

Remarks—The leaves are similar to G. spatulata as illustrated by Pant and Singh (1971, Pl. 10, fig. 60), Chandra and Surange (1979, Pl. 8, fig. 1, Pl. 12, fig. 5, Pl. 17, fig. 7, Pl. 18, fig. 1, Pl. 27, fig. 1), Tewari and Srivastava (2000b, Pl. 1, fig. 6) and Singh and Chandra (2000, Pl. 1, fig. 5), in shape, nature of midrib and venation pattern. Leaves also match with G. spatulata described by Tewari (2007, Pl. 1, fig. 7, Pl. 2, fig. 2, Pl. 5, fig. 1, Pl. 7, fig. 6) and Singh et al.

(2011, Pl. 7, figs 1, 3).

No. of specimens—Four (40920, 40921, 40922A, 40923).

Glossopteris sp.

(Pl. 3.5)

Description—Single leaf is present in the collection. Leaf small, incomplete, only one side of the lamina is preserved, 36 mm long and 10 mm broad, shape oblong, apex and base are absent, midrib broad, striate, margin entire. Secondary veins arise at 45° from the midrib and meet the margin at about 60°. Veins dichotomize and anastomose to form broad, polygonal meshes of uniform size. Meshes are 2–4 mm long and 0.5–0.6 mm broad. Density of veins is 11–16 veins per cm in preserved part of the lamina.

Remarks—The small size of the leaf with its broad median region makes it significantly different from other known species of Glossopteris. Since the specimen is fragmentary, it is not possible to constitute a new species.

No. of specimens—One (40922B).

Order—CORDAITALES

Genus—NOEGGERATHIOPSIS Feistmantel, 1879 Type species—Noeggerathiopsis hislopii (Bunbury)

Feistmantel, 1879

Noeggerathiopsis hislopii (Bunbury) Feistmantel, 1879 (Pl. 3.6–3.8)

PLATE 3

(Scale bar= 1 cm)

1. Glossopteris longicaulis Feistmantel, 1879, BSIP Museum Specimen No. 40898B (arrow indicates the petiole).

2. Glossopteris spatulata Pant & Singh, 1971, BSIP Museum Specimen No. 40920.

5. Glossopteris sp., BSIP Museum Specimen No. 40922B.

6. Noeggerathiopsis hislopii (Bunbury) Feistmantel, 1879, BSIP Museum Specimen No. 40924.

(9)

PLATE 3

(10)

Description—Nine specimens both–complete and fragmentary are present in the collection. The leaves are lanceolate–spatulate, 43–106 mm long and 19–29 mm wide, apex obtuse, base tapering, narrow, margin entire. Several parallel veins arise from the base, run straight and dichotomize frequently along their course. Vein density is 12–14 veins per cm in lower part and 17–20 veins per cm in upper part of the leaf.

Remarks—The leaves are identical to Noeggerathiopsis hislopii figured by Feistmantel (1879, Pl. 12, fig. 5, Pl. 19, figs 1–6, Pl. 20, fig. 1) in shape and venation pattern.

No. of specimens—Nine (40924, 40925, 40926, 40927, 40928A, 40928B, 40929, 40930, 40931).

CONCLUDING REMARKS

The Glossopteris flora is well known from almost all the major Gondwana basins of India. However, plant fossil records from the Sohagpur Coalfield of South Rewa Basin are so far sporadic. The floral assemblage from the Barakar Formation of Sharda Open Cast Mine, Sohagpur Coalfield, Shahdol District, Madhya Pradesh comprises the order Equisetales of pteridophytes and, the orders Glossopteridales and Cordaitales of gymnosperms. Equisetales includes equisetalean axes and Cordaitales is represented by Noeggerathiopsis hislopii.

Glossopteridales dominates the assemblage and is represented by one species of Gangamopteris, G. intermedia, and seven species of Glossopteris, namely G. communis, G. gigas, G. giridihensis, G. indica, G. longicaulis, G. spatulata and Glossopteris sp. The present floral assemblage is the first record from the area and is broadly comparable with those of the Barakar Formation of the Damodar (Srivastava, 1992;

Srivastava & Tewari, 1996; Tewari & Srivastava, 1996), Mahanadi (Singh & Chandra, 1996; Singh et al., 2006a, b, 2007), Wardha (Tewari, 2008), Godavari (Tewari & Jha, 2006), Rajmahal (Maheshwari & Prakash, 1965) and Satpura (Srivastava & Agnihotri, 2009; Srivastava et al., 2012) basins of India (Table 1). The presence of Gangamopteris and Noeggerathiopsis leaves in the assemblage is very characteristic and normally such association is correlated with the underlying flora of the Karharbari Formation. However, further studies from the lower part of the Barakar Formation of South Karanpura (Kulkarni, 1971), Raniganj (Srivastava, 1992) and Umrer (Tewari et al,. 2012) coalfields indicate their continued presence in the onward flora. The presence of the above mentioned plant groups in the Barakar sediments of the Sharda Open Cast Mine suggests their importance in the formation of coal in the area. Further, the occurrence of large leaves like those of Glossopteris communis, G. gigas, G. indica and G. spatulata in these sediments supports the existence of conducive warm, temperate and humid climatic condition during the coal formation (Lele, 1976; Chandra &

Chandra, 1987; Chandra, 1992).

Acknowledgements—We thank Prof. Sunil Bajpai, Director, Birbal Sahni Institute of Palaeobotany (BSIP), Lucknow, India, for extending necessary facilities to carry out this research work and granting the permission to publish the data (BSIP/RDCC/Publication no. 83/2016). Sincere thanks are due to Dr A.K. Srivastava, Prof. Sundeep K. Pandita and Dr Anju Saxena for reviewing the manuscript and providing constructive suggestions. The Chief General Manager, Sohagpur Coalfield, Shahdol is thanked for permission to collect the samples and Mr N.P. Vishwakarma, Senior Surveyor, Area Survey Office, Sohagpur Coalfield is gratefully acknowledged for his constant help during the collection of samples and providing necessary geological details. Mr Pradeep Mohan, Technical Officer–D, Birbal Sahni Institute of Palaeobotany, Lucknow is thanked for photography of the specimens. A. Jasper acknowledges Alexander von Humboldt Foundation (Germany BRA 1137359 STPCAPES), FAPERGS, CAPES and CNPq (Brazil). D. Uhl acknowledges the “Science without Borders Program” (Project A072/2013–CAPES–

Brazil).

REFERENCES

Brongniart A 1828. Histoire des végétaux fossils ou recherché botaniques et géologiques sur les végétaux renfermés dans les diverse couches du globe. Prodomus d’une histoire des vegetaux fossils 1, Dufour & D’

Ocagne, Paris, 488 pp.

Chandra A & Srivastava AK 1982. Plant fossils from the Talchir and coal bearing formations of South Rewa Gondwana Basin, India and their biostratigraphical significance. Palaeobotanist 30: 143–167.

Chandra S 1992. Changing patterns of the Permian Gondwana vegetation.

Palaeobotanist 40: 73–100.

Chandra S & Chandra A 1987. Vegetational changes and their climatic implications in coal–bearing Gondwana. Palaeobotanist 36: 74–86.

Chandra S & Singh KJ 1992. The genus Glossopteris from the Late Permian beds of Handapa, Orissa, India. Review of Palaeobotany and Palynology 75: 183–218.

Chandra S & Surange KR 1979. Revision of the Indian Species of Glossopteris. Monograph 2. Birbal Sahni Institute of Palaeobotany, Lucknow: 1–291.

Dhanam K, Kumar PS, Mysaiah D, Prasad PP & Seshunarayana T 2013.

High resolution seismic imaging of the Sohagpur Gondwana basin, central India: Evidence for syn sedimentary subsidence and faulting. Journal of Earth System Science 112: 1495–1505.

Feistmantel O 1876. Notes on the age of some fossil floras in India—VII.

Flora of the Jabalpur Group in South Rewah, near Jabalpur, and in the Satpura Basin. Records of the Geological Survey of India 9: 125–129.

Feistmantel O 1879. The fossil flora of the Lower Gondwanas—1. The flora of the Talchir–Karharbari beds. Memoirs of the Geological Survey of India, Palaeontologia indica 12, 3(1): 1–48.

Feistmantel O 1882. The fossil flora of the Gondwana system. 4.1. The fossil flora of the South Rewa Gondwana Basin. Memoirs of Geological Survey of India. Palaeontologia Indica ser. 12: 1–52.

Feistmantel O 1890. Geological and palaeontological relations of the coal and plant–bearing beds of Palaeozoic and Mesozoic age in eastern Australia and Tasmania; with special reference to the fossil flora. Memoirs of the Geological Survey of New South Wales, Palaeontology 3: 1–185.

Hughes TWH 1881. Notes on the South Rewah Gondwana Basin. Records of Geological Survey of India 14: 126–156.

Hughes TWH 1884. The southern coalfields of the Rewah Gondwana Basin:

Umaria, Korar, Johilla, Sohagpur, Kurasia, Koreagarh, Jhilmili. Records

(11)

of Geological Survey of India 24: 1–68.

Kulkarni S 1971. Glossopteris and Gangamopteris species from south Karanpura Coalfield. Palaeobotanist 18: 297–304.

Lawrence GHM 1955. An Introduction to Plant Taxonomy. The Macmillan Company, New York, 179 pp.

Lele KM 1976. Palaeoclimatic implications of Gondwana flora. Geophytology 6: 207–229.

Maheshwari HK & Prakash G 1965. Studies in the Glossopteris flora of India—21. Plant megafossils from the Lower Gondwana exposures along Bansloi River in Rajmahal Hills, Bihar. Palaeobotanist 13: 115–128.

Maheshwari HK & Tewari R 1992. Epidermal morphology of some Indian species of the genus Glossopteris Brongniart. Palaeobotanist 39: 338–380.

Maithy PK 1965. Studies in the Glossopteris flora of India—26.

Glossopteridales from the Karharbari beds, Giridih Coalfield, India.

Palaeobotanist 13: 248–263.

Maithy PK, Bindal CM, Bhushan SK, Sharma S, Banerji DC & Kumar G 2006. Lower Gondwana plant fossils from Arunachal Pradesh, Lesser Himalaya and their age. Journal of Geological Society of India 68:

316–326.

McCoy F 1875. Geological Survey of Victoria, Prodromus of the Palaeontology of Victoria, Decade II: 11–13.

Melville R 1969. Leaf venation patterns and the origin of the angiosperms.

Nature 224: 121–125.

Pant DD & Gupta KL 1968. Cuticular structure of some Indian Lower Gondwana species of Glossopteris Brongniart—Part I. Palaeontographica B 124: 45–81.

Pant DD & Singh KB 1971. Cuticular structure of some Indian Lower Gondwana species of Glossopteris Brongniart—Part III. Palaeontographica B 135: 1–40.

Pareek HS 1987. Petrographic, chemical and trace–elemental composition of the coal of Sohagpur Coalfield, Madhya Pradesh, India. International Journal of Coal Geology 9: 187–207.

Raja Rao CS 1983. Coalfields of India Vol. III Coal Resources of Madhya Pradesh and Jammu and Kashmir. Bulletin of Geological Survey of India (Series A) 45: 1–204.

Schimper WP 1869. Traité de Paléontologie végétale—1, J. b. Bailliere et Fils, Paris, 738 pp.

Singh G, Maithy S & Bose MN 1982. Upper Palaeozoic flora of Kashmir Himalaya. Palaeobotanist 30: 185–232.

Singh KJ & Chandra S 1996. Plant fossils from the exposure near Gopal Prasad Village, Talchir Coalfield Orissa with remarks on the age of the bed. Geophytology 26: 69–75.

Singh KJ & Chandra S 2000. Additional palaeobotanical information from Madhupur Village, Talchir Coalfield, Orissa, India. Palaeobotanist 49:

385–398.

Singh KJ, Goswami S & Chandra S 2006a. The genus Glossopteris from

lower Gondwana formations of Ib–River Coalfield, Orissa, India. Journal of the Palaeontological Society of India 51: 81–107.

Singh KJ, Goswami S & Chandra S 2006b. Megafloral assemblage similar to Karharbari biozone from Talchir Coalfield of Mahanadi Basin, Orissa.

Journal of the Geological Society of India 68: 77–287.

Singh KJ, Goswami S & Chandra S 2007. Occurrence of Cordaitales from Lower Gondwana sediments of Ib–River Coalfield, Orissa, India. An Indian Scenario. Journal of Asian Earth Sciences 29: 666–684.

Singh KJ, Goswami S & Srivastava G 2011. Palaeodiversity in the genus Glossopteris from the Lower Gondwana rocks of the Korba Coalfield, Chhattisgarh State, India. Journal of the Palaeontological Society of India 56: 39–59.

Singh KJ & Saxena A 2015. End Permian (Lopingian) floral diversity in Singrauli Coalfield: evidences from Jhingurdah Colliery, Son–Mahanadi Basin, India. Journal of the Paleontological Society of India 60: 97–112.

Srivastava AK 1992. Plant fossil assemblages from the Barakar Formation of Raniganj Coalfield, India. Palaeobotanist 39: 281–302.

Srivastava AK & Agnihotri D 2009. Palaeobotanical perspectives of Satpura Gondwana Basin, Madhya Pradesh. Earth System Sciences (Editors–

Kumar A, Kushwaha RAS & Thakur Balesh) 2: 581–595.

Srivastava AK & Tewari R 1996. Plant fossils from the Barakar Formation, Auranga Coalfield, Bihar. Geophytology 26: 83–88.

Srivastava AK, Saxena A & Agnihotri D 2012. Morphological and Stratigraphical significance of Lower Gondwana plant fossils of Mohpani Coalfield, Satpura Gondwana Basin, Madhya Pradesh. Journal of Geological Society of India 80: 676–684.

Tewari R 2007. The Glossopteris flora from the Kamptee Coalfield, Wardha Basin, Maharashtra, India. Palaeontographica B 277: 43–64.

Tewari R 2008. The genus Glossopteris Brongniart from the Kamthi Formation of Camp IV area, Wardha Valley Coalfield, Wardha Basin, Maharashtra, India. Journal of Palaeontological Society of India 53:

19–30.

Tewari R & Jha N 2006. Occurrence of plant mega and microfossils of Barakar and Raniganj formations of Manuguru area, Godavari Graben, Andhra Pradesh. Journal of Geological Society of India 67: 101–112.

Tewari R & Srivastava AK 1996. Plant fossils from the Barakar Formation, Jharia Coalfield, Bihar. Geophytology 25: 35–39.

Tewari R & Srivastava AK 2000a. Plant fossil assemblage from the Talchir Formation, Auranga Coalfield, Bihar, India. Palaeobotanist 49: 23–30.

Tewari R & Srivastava AK 2000b. Plant fossils from Bhareli Formation of Arunachal Pradesh, North–East Himalaya, India. Palaeobotanist 49:

209–217.

Tewari R, Pandita SK, Agnihotri D, Pillai SSK & Bernardes–De–Oliveira MEC 2012. An Early Permian Glossopteris flora from the Umrer Coalfield, Wardha Basin, Maharashtra, India. Alcheringa 36: 355–371.